pigweed / third_party / github / STMicroelectronics / cmsis_core / 7dd288b23bf605a3a2fafa81a29d2c96a2fd83ce / . / DSP_Lib / Source / FilteringFunctions / arm_conv_opt_q7.c

/* ---------------------------------------------------------------------- | |

* Copyright (C) 2010-2014 ARM Limited. All rights reserved. | |

* | |

* $Date: 19. March 2015 | |

* $Revision: V.1.4.5 | |

* | |

* Project: CMSIS DSP Library | |

* Title: arm_conv_opt_q7.c | |

* | |

* Description: Convolution of Q7 sequences. | |

* | |

* Target Processor: Cortex-M4/Cortex-M3/Cortex-M0 | |

* | |

* Redistribution and use in source and binary forms, with or without | |

* modification, are permitted provided that the following conditions | |

* are met: | |

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* notice, this list of conditions and the following disclaimer. | |

* - Redistributions in binary form must reproduce the above copyright | |

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* distribution. | |

* - Neither the name of ARM LIMITED nor the names of its contributors | |

* may be used to endorse or promote products derived from this | |

* software without specific prior written permission. | |

* | |

* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS | |

* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT | |

* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS | |

* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE | |

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* -------------------------------------------------------------------- */ | |

#include "arm_math.h" | |

/** | |

* @ingroup groupFilters | |

*/ | |

/** | |

* @addtogroup Conv | |

* @{ | |

*/ | |

/** | |

* @brief Convolution of Q7 sequences. | |

* @param[in] *pSrcA points to the first input sequence. | |

* @param[in] srcALen length of the first input sequence. | |

* @param[in] *pSrcB points to the second input sequence. | |

* @param[in] srcBLen length of the second input sequence. | |

* @param[out] *pDst points to the location where the output result is written. Length srcALen+srcBLen-1. | |

* @param[in] *pScratch1 points to scratch buffer(of type q15_t) of size max(srcALen, srcBLen) + 2*min(srcALen, srcBLen) - 2. | |

* @param[in] *pScratch2 points to scratch buffer (of type q15_t) of size min(srcALen, srcBLen). | |

* @return none. | |

* | |

* \par Restrictions | |

* If the silicon does not support unaligned memory access enable the macro UNALIGNED_SUPPORT_DISABLE | |

* In this case input, output, scratch1 and scratch2 buffers should be aligned by 32-bit | |

* | |

* @details | |

* <b>Scaling and Overflow Behavior:</b> | |

* | |

* \par | |

* The function is implemented using a 32-bit internal accumulator. | |

* Both the inputs are represented in 1.7 format and multiplications yield a 2.14 result. | |

* The 2.14 intermediate results are accumulated in a 32-bit accumulator in 18.14 format. | |

* This approach provides 17 guard bits and there is no risk of overflow as long as <code>max(srcALen, srcBLen)<131072</code>. | |

* The 18.14 result is then truncated to 18.7 format by discarding the low 7 bits and then saturated to 1.7 format. | |

* | |

*/ | |

void arm_conv_opt_q7( | |

q7_t * pSrcA, | |

uint32_t srcALen, | |

q7_t * pSrcB, | |

uint32_t srcBLen, | |

q7_t * pDst, | |

q15_t * pScratch1, | |

q15_t * pScratch2) | |

{ | |

q15_t *pScr2, *pScr1; /* Intermediate pointers for scratch pointers */ | |

q15_t x4; /* Temporary input variable */ | |

q7_t *pIn1, *pIn2; /* inputA and inputB pointer */ | |

uint32_t j, k, blkCnt, tapCnt; /* loop counter */ | |

q7_t *px; /* Temporary input1 pointer */ | |

q15_t *py; /* Temporary input2 pointer */ | |

q31_t acc0, acc1, acc2, acc3; /* Accumulator */ | |

q31_t x1, x2, x3, y1; /* Temporary input variables */ | |

q7_t *pOut = pDst; /* output pointer */ | |

q7_t out0, out1, out2, out3; /* temporary variables */ | |

/* The algorithm implementation is based on the lengths of the inputs. */ | |

/* srcB is always made to slide across srcA. */ | |

/* So srcBLen is always considered as shorter or equal to srcALen */ | |

if(srcALen >= srcBLen) | |

{ | |

/* Initialization of inputA pointer */ | |

pIn1 = pSrcA; | |

/* Initialization of inputB pointer */ | |

pIn2 = pSrcB; | |

} | |

else | |

{ | |

/* Initialization of inputA pointer */ | |

pIn1 = pSrcB; | |

/* Initialization of inputB pointer */ | |

pIn2 = pSrcA; | |

/* srcBLen is always considered as shorter or equal to srcALen */ | |

j = srcBLen; | |

srcBLen = srcALen; | |

srcALen = j; | |

} | |

/* pointer to take end of scratch2 buffer */ | |

pScr2 = pScratch2; | |

/* points to smaller length sequence */ | |

px = pIn2 + srcBLen - 1; | |

/* Apply loop unrolling and do 4 Copies simultaneously. */ | |

k = srcBLen >> 2u; | |

/* First part of the processing with loop unrolling copies 4 data points at a time. | |

** a second loop below copies for the remaining 1 to 3 samples. */ | |

while(k > 0u) | |

{ | |

/* copy second buffer in reversal manner */ | |

x4 = (q15_t) * px--; | |

*pScr2++ = x4; | |

x4 = (q15_t) * px--; | |

*pScr2++ = x4; | |

x4 = (q15_t) * px--; | |

*pScr2++ = x4; | |

x4 = (q15_t) * px--; | |

*pScr2++ = x4; | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* If the count is not a multiple of 4, copy remaining samples here. | |

** No loop unrolling is used. */ | |

k = srcBLen % 0x4u; | |

while(k > 0u) | |

{ | |

/* copy second buffer in reversal manner for remaining samples */ | |

x4 = (q15_t) * px--; | |

*pScr2++ = x4; | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* Initialze temporary scratch pointer */ | |

pScr1 = pScratch1; | |

/* Fill (srcBLen - 1u) zeros in scratch buffer */ | |

arm_fill_q15(0, pScr1, (srcBLen - 1u)); | |

/* Update temporary scratch pointer */ | |

pScr1 += (srcBLen - 1u); | |

/* Copy (srcALen) samples in scratch buffer */ | |

/* Apply loop unrolling and do 4 Copies simultaneously. */ | |

k = srcALen >> 2u; | |

/* First part of the processing with loop unrolling copies 4 data points at a time. | |

** a second loop below copies for the remaining 1 to 3 samples. */ | |

while(k > 0u) | |

{ | |

/* copy second buffer in reversal manner */ | |

x4 = (q15_t) * pIn1++; | |

*pScr1++ = x4; | |

x4 = (q15_t) * pIn1++; | |

*pScr1++ = x4; | |

x4 = (q15_t) * pIn1++; | |

*pScr1++ = x4; | |

x4 = (q15_t) * pIn1++; | |

*pScr1++ = x4; | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* If the count is not a multiple of 4, copy remaining samples here. | |

** No loop unrolling is used. */ | |

k = srcALen % 0x4u; | |

while(k > 0u) | |

{ | |

/* copy second buffer in reversal manner for remaining samples */ | |

x4 = (q15_t) * pIn1++; | |

*pScr1++ = x4; | |

/* Decrement the loop counter */ | |

k--; | |

} | |

#ifndef UNALIGNED_SUPPORT_DISABLE | |

/* Fill (srcBLen - 1u) zeros at end of scratch buffer */ | |

arm_fill_q15(0, pScr1, (srcBLen - 1u)); | |

/* Update pointer */ | |

pScr1 += (srcBLen - 1u); | |

#else | |

/* Apply loop unrolling and do 4 Copies simultaneously. */ | |

k = (srcBLen - 1u) >> 2u; | |

/* First part of the processing with loop unrolling copies 4 data points at a time. | |

** a second loop below copies for the remaining 1 to 3 samples. */ | |

while(k > 0u) | |

{ | |

/* copy second buffer in reversal manner */ | |

*pScr1++ = 0; | |

*pScr1++ = 0; | |

*pScr1++ = 0; | |

*pScr1++ = 0; | |

/* Decrement the loop counter */ | |

k--; | |

} | |

/* If the count is not a multiple of 4, copy remaining samples here. | |

** No loop unrolling is used. */ | |

k = (srcBLen - 1u) % 0x4u; | |

while(k > 0u) | |

{ | |

/* copy second buffer in reversal manner for remaining samples */ | |

*pScr1++ = 0; | |

/* Decrement the loop counter */ | |

k--; | |

} | |

#endif | |

/* Temporary pointer for scratch2 */ | |

py = pScratch2; | |

/* Initialization of pIn2 pointer */ | |

pIn2 = (q7_t *) py; | |

pScr2 = py; | |

/* Actual convolution process starts here */ | |

blkCnt = (srcALen + srcBLen - 1u) >> 2; | |

while(blkCnt > 0) | |

{ | |

/* Initialze temporary scratch pointer as scratch1 */ | |

pScr1 = pScratch1; | |

/* Clear Accumlators */ | |

acc0 = 0; | |

acc1 = 0; | |

acc2 = 0; | |

acc3 = 0; | |

/* Read two samples from scratch1 buffer */ | |

x1 = *__SIMD32(pScr1)++; | |

/* Read next two samples from scratch1 buffer */ | |

x2 = *__SIMD32(pScr1)++; | |

tapCnt = (srcBLen) >> 2u; | |

while(tapCnt > 0u) | |

{ | |

/* Read four samples from smaller buffer */ | |

y1 = _SIMD32_OFFSET(pScr2); | |

/* multiply and accumlate */ | |

acc0 = __SMLAD(x1, y1, acc0); | |

acc2 = __SMLAD(x2, y1, acc2); | |

/* pack input data */ | |

#ifndef ARM_MATH_BIG_ENDIAN | |

x3 = __PKHBT(x2, x1, 0); | |

#else | |

x3 = __PKHBT(x1, x2, 0); | |

#endif | |

/* multiply and accumlate */ | |

acc1 = __SMLADX(x3, y1, acc1); | |

/* Read next two samples from scratch1 buffer */ | |

x1 = *__SIMD32(pScr1)++; | |

/* pack input data */ | |

#ifndef ARM_MATH_BIG_ENDIAN | |

x3 = __PKHBT(x1, x2, 0); | |

#else | |

x3 = __PKHBT(x2, x1, 0); | |

#endif | |

acc3 = __SMLADX(x3, y1, acc3); | |

/* Read four samples from smaller buffer */ | |

y1 = _SIMD32_OFFSET(pScr2 + 2u); | |

acc0 = __SMLAD(x2, y1, acc0); | |

acc2 = __SMLAD(x1, y1, acc2); | |

acc1 = __SMLADX(x3, y1, acc1); | |

x2 = *__SIMD32(pScr1)++; | |

#ifndef ARM_MATH_BIG_ENDIAN | |

x3 = __PKHBT(x2, x1, 0); | |

#else | |

x3 = __PKHBT(x1, x2, 0); | |

#endif | |

acc3 = __SMLADX(x3, y1, acc3); | |

pScr2 += 4u; | |

/* Decrement the loop counter */ | |

tapCnt--; | |

} | |

/* Update scratch pointer for remaining samples of smaller length sequence */ | |

pScr1 -= 4u; | |

/* apply same above for remaining samples of smaller length sequence */ | |

tapCnt = (srcBLen) & 3u; | |

while(tapCnt > 0u) | |

{ | |

/* accumlate the results */ | |

acc0 += (*pScr1++ * *pScr2); | |

acc1 += (*pScr1++ * *pScr2); | |

acc2 += (*pScr1++ * *pScr2); | |

acc3 += (*pScr1++ * *pScr2++); | |

pScr1 -= 3u; | |

/* Decrement the loop counter */ | |

tapCnt--; | |

} | |

blkCnt--; | |

/* Store the result in the accumulator in the destination buffer. */ | |

out0 = (q7_t) (__SSAT(acc0 >> 7u, 8)); | |

out1 = (q7_t) (__SSAT(acc1 >> 7u, 8)); | |

out2 = (q7_t) (__SSAT(acc2 >> 7u, 8)); | |

out3 = (q7_t) (__SSAT(acc3 >> 7u, 8)); | |

*__SIMD32(pOut)++ = __PACKq7(out0, out1, out2, out3); | |

/* Initialization of inputB pointer */ | |

pScr2 = py; | |

pScratch1 += 4u; | |

} | |

blkCnt = (srcALen + srcBLen - 1u) & 0x3; | |

/* Calculate convolution for remaining samples of Bigger length sequence */ | |

while(blkCnt > 0) | |

{ | |

/* Initialze temporary scratch pointer as scratch1 */ | |

pScr1 = pScratch1; | |

/* Clear Accumlators */ | |

acc0 = 0; | |

tapCnt = (srcBLen) >> 1u; | |

while(tapCnt > 0u) | |

{ | |

acc0 += (*pScr1++ * *pScr2++); | |

acc0 += (*pScr1++ * *pScr2++); | |

/* Decrement the loop counter */ | |

tapCnt--; | |

} | |

tapCnt = (srcBLen) & 1u; | |

/* apply same above for remaining samples of smaller length sequence */ | |

while(tapCnt > 0u) | |

{ | |

/* accumlate the results */ | |

acc0 += (*pScr1++ * *pScr2++); | |

/* Decrement the loop counter */ | |

tapCnt--; | |

} | |

blkCnt--; | |

/* Store the result in the accumulator in the destination buffer. */ | |

*pOut++ = (q7_t) (__SSAT(acc0 >> 7u, 8)); | |

/* Initialization of inputB pointer */ | |

pScr2 = py; | |

pScratch1 += 1u; | |

} | |

} | |

/** | |

* @} end of Conv group | |

*/ |